Buggy code:
public class Parser { private static Event oldEvent ; private static ReservedEvent oldReservedEvent ; private static GenericEvent oldGenericEvent ; private static String recordedDate ; private boolean isNameDefined = true ; private boolean isAfterOn = false ; private boolean isAfterNext = false ; private boolean isEdit = false ; private final String PATTERN_SPACE = "(\\s)" ; private final String PATTERN_AM_OR_PM = "(\\b(am)\\b|\\b(pm)\\b)" ; private final String PATTERN_AT = "(\\bat\\b)" ; private final String PATTERN_AT_OR_BY_OR_NEXT = "(\\b(at)\\b|\\b(by)\\b|\\b(next)\\b)" ; private final String PATTERN_AT_OR_BY = "(\\b(at)\\b|\\b(by)\\b)" ; private final String PATTERN_COLUMN = "(\\b(:)\\b)" ; private final String PATTERN_AND = "(\\b(and)\\b|\\b(&)\\b)" ; private final String PATTERN_TO = "(\\bto\\b)" ; private final String PATTERN_BEFORE = "(\\bbefore\\b)" ; private final String PATTERN_AFTER = "(\\bafter\\b)" ; private final String PATTERN_NEXT = "(\\bnext\\b)" ; private final String PATTERN_AFTER_NEXT = "(\\bafter<seq2seq4repair_space>next\\b)" ; private final String PATTERN_TODAY = "(\\btoday\\b)" ; private final String PATTERN_TOMORROW = "(\\btomorrow\\b)" ; private final String PATTERN_TOD = "(\\btod\\b)" ; private final String PATTERN_TOM = "(\\btom\\b)" ; private final String PATTERN_YES = "(\\byes\\b)" ; private final String PATTERN_PREP_ALL = "(\\b(on)\\b|\\b(by)\\b|\\b(from)\\b|\\b(at)\\b|\\b(next)\\b|\\b(before)\\b|\\b(after<seq2seq4repair_space>next)\\b)" ; private final String PATTERN_KEYWORD_ALL = "(\\b(starttime)\\b|\\b(startdate)\\b|\\b(endtime)\\b|\\b(enddate)\\b|\\b(location)\\b|\\b(note)\\b)" ; private final String PREP_ON = "on" ; private final String PREP_AT = "at" ; private final String PREP_BY = "by" ; private final String PREP_FROM = "from" ; private final String PREP_NEXT = "next" ; private final String PREP_BEFORE = "before" ; private final String PREP_AFTER_NEXT = "after<seq2seq4repair_space>next" ; private final String KEY_START_TIME = "starttime" ; private final String KEY_START_DATE = "startdate" ; private final String KEY_END_TIME = "endtime" ; private final String KEY_END_DATE = "enddate" ; private final String KEY_NOTE = "note" ; private final String KEY_LOCATION = "location" ; private final String TIME_BEFORE_MIDNIGHT = "23:59" ; private final String TIME_BEFORE_MIDNIGHT_SEC = "23:59:01" ; private final String TIME_MIDNIGHT = "00:00" ; private final String ERROR_DATE_FORMAT = "The<seq2seq4repair_space>input<seq2seq4repair_space>date<seq2seq4repair_space>format<seq2seq4repair_space>is<seq2seq4repair_space>not<seq2seq4repair_space>supported" ; private final String TAB_UNDETERMINED = "UNDETERMINE" ; private final String TAB_COMPLETED = "COMPLETE" ; private final String TAB_INCOMPLETE = "INCOMPLETE" ; private final int DAYS_IN_WEEK = 7 ; public Command parseCommand ( String input ) { } public GenericEvent testingDeterminedStuff ( String input ) { } public GenericEvent testingReservedStuff ( String input ) { } public void cloneEvent ( Event eventToBeCloned , Event event ) { } public void cloneReservedEvent ( ReservedEvent eventToBeCloned , Event event ) { } public void cloneReservedTimePair ( ArrayList < TimePair > times , ReservedEvent reservedEvent ) { } private GenericEvent decodeAddData ( Event task , String input ) { } private ReservedEvent decodeReservedData ( Event task , String input ) { } private Event decodeImportExportData ( Event task , String input ) { } private Status decodeChangeTab ( String input ) { } private Event decodeSelectData ( Event task , String input ) { } private Event decodeDeleteData ( Event task , String input ) { } private Event decodeEditData ( Event task , String input ) { } private GenericEvent decodeEditReservedData ( Event task , ArrayList < TimePair > prevReservedTimes , String input ) { } private Event determineQuotedInput ( Event task , String input ) { } private Event decodeDataFromInput ( Event task , String input ) { } private Event classifyDataFromKeyword ( Event task , String input , String keyword , int startIndex , int endIndex ) { } private Event classifyDataFromPreposition ( Event task , String input , String preposition , int startIndex , int endIndex ) throws ParseException { } private Event extractDateFromNextPreposition ( Event task , String input , int newStartIndex , int newEndIndex , SimpleDateFormat formatToString ) { } private void extractDateFromAtPreposition ( Event task , String input , int newStartIndex , int newEndIndex , SimpleDateFormat formatToString ) { } private void extractDateFromToPreposition ( Event task , String input , int newStartIndex , int newEndIndex ) { } private void extractDateFromFromPreposition ( Event task , String input , int newStartIndex , int newEndIndex , SimpleDateFormat formatToString ) { } private void extractDateFromByPreposition ( Event task , String input , int newStartIndex , int newEndIndex , SimpleDateFormat formatToString ) { } private void extractDateFromOnPreposition ( Event task , String input , int newStartIndex , int newEndIndex , SimpleDateFormat formatToString ) { } private String [ ] extractTimeFromDate ( String date ) { } private String extractLocationFromAt ( Event event , String input ) { } private String extractDescription ( Event event , String input ) { } private int [ ] matchPatternOfFirstOccurrence ( String desiredPattern , String input ) { } private static int [ ] matchPatternOfLastOccurrence ( String desiredPattern , String input ) { } private Event determineCategory ( Event event ) { } private Category classifyCategory ( String userInput ) { } private Status classifyStatus ( String userInput ) { } private CommandType getCommandType ( String command ) { } private String getFirstWord ( String input ) { } private String removeFirstWord ( String input ) { <START_BUG> return input . replace ( getFirstWord ( input ) , "" ) . trim ( ) ; <END_BUG> } }

Fix:
return input . replaceFirst ( ( ( "\\b" + ( getFirstWord ( input ) ) ) + "\\b" ) , "" ) . trim ( ) ;